Selective modification of build strategy parameter(s) for additive manufacturing

ABSTRACT

A computerized method, system, program product and additive manufacturing (AM) system are disclosed. Embodiments provide for modifying object code representative of an object to be physically generated layer by layer by a computerized AM system using the object code. The computerized method may include providing an interface to allow a user to manually: select a region within the object in the object code, the object code including a plurality of pre-assigned build strategy parameters for the object that control operation of the computerized AM system, and selectively modify a build strategy parameter in the selected region in the object code to change an operation of the computerized AM system from the plurality of pre-assigned build strategy parameters during building of the object by the computerized AM system.

This application is related to co-pending U.S. patent application Ser.Nos. 15/677,406 and 15/677,426 all filed concurrently.

BACKGROUND OF THE INVENTION

The disclosure relates generally to additive manufacturing, and moreparticularly, to a method of selectively modifying an additivemanufacturing build strategy parameter for a region of an object.

The pace of change and improvement in the realms of power generation,aviation, and other fields has accompanied extensive research formanufacturing objects used in these fields. Conventional manufacture ofobjects, such as metallic, plastic or ceramic composite objects,generally includes milling or cutting away regions from a slab ofmaterial before treating and modifying the cut material to yield a part,which may have been simulated using computer models, e.g., in draftingsoftware. Manufactured objects which may be formed from metal caninclude, e.g., airfoil objects for installation in a turbomachine suchas an aircraft engine or power generation system.

Additive manufacturing (AM) includes a wide variety of processes ofproducing an object through the successive layering of material ratherthan the removal of material. Additive manufacturing can create complexgeometries without the use of any sort of tools, molds or fixtures, andwith little or no waste material. Instead of machining objects fromsolid billets of material, much of which is cut away and discarded, theonly material used in additive manufacturing is what is required toshape the object.

Additive manufacturing techniques typically include taking athree-dimensional (3D) computer aided design (CAD) object file of theobject to be formed, and electronically slicing the object into layers(e.g., 18-102 micrometers thick) to create a file with a two-dimensionalimage of each layer (including vectors, images or coordinates) that canbe used to manufacture the object. The 3D CAD object file can be createdin any known fashion, e.g., computer aided design (CAD) system, a 3Dscanner, or digital photography and photogrammetry software. The 3D CADobject file may undergo any necessary repair to address errors (e.g.,holes, etc.) therein, and may have any CAD format such as a StandardTessellation Language (STL) file. The 3D CAD object file may then beprocessed by a preparation software system (sometimes referred to as a“slicer”) that interprets the 3D CAD object file and electronicallyslices it such that the object can be built by different types ofadditive manufacturing systems. The preparation software system may bepart of the CAD system, part of the computerized AM system or separatefrom both. The preparation software system may output an object codefile in any format capable of being used by the desired computerized AMsystem. For example, the object code file may be an STL file or anadditive manufacturing file (AMF), the latter of which is aninternational standard that is an extensible markup-language (XML) basedformat designed to allow any CAD software to describe the shape andcomposition of any three-dimensional object to be fabricated on any AMprinter. Depending on the type of additive manufacturing used, materiallayers are selectively dispensed, sintered, formed, deposited, etc., tocreate the object per the object code file.

One form of powder bed infusion (referred to herein as metal powderadditive manufacturing) may include direct metal laser melting (DMLM)(also referred to as selective laser melting (SLM)). In metal powderadditive manufacturing, metal powder layers are sequentially meltedtogether to form the object. More specifically, fine metal powder layersare sequentially melted after being uniformly distributed using anapplicator on a metal powder bed. Each applicator includes an applicatorelement in the form of a lip, brush, blade or roller made of metal,plastic, ceramic, carbon fibers or rubber that spreads the metal powderevenly over the build platform. The metal powder bed can be moved in avertical axis. The process takes place in a processing chamber having aprecisely controlled atmosphere. Once each layer is created, each twodimensional slice of the object geometry can be fused by selectivelymelting the metal powder. The melting may be performed by a high poweredirradiation beam, such as a 100 Watt ytterbium laser, to fully weld(melt) the metal powder to form a solid metal. The irradiation beammoves in the X-Y direction, and has an intensity sufficient to fullyweld (melt) the metal powder to form a solid metal. The metal powder bedmay be lowered for each subsequent two dimensional layer, and theprocess repeats until the object is completely formed.

Some metal powder AM systems employ two or more irradiation devices,e.g., high powered lasers or electron beams, that work together to forman object. Using two or more irradiation devices may be advantageous tocreate larger objects faster, to allow use of larger build areas orcomputerized AM systems, and/or improve the accuracy of a build.Typically, for a multiple irradiation device computerized AM system,each two-dimensional image of each layer includes assignments fordifferent irradiation devices to form different regions of the object.The irradiation device assignment can be provided by any of the AM filesystems, i.e., the CAD system that creates the original layout of theobject, a preparation software system, or the control system of themultiple irradiation device computerized AM system.

One challenge with current AM techniques is that build strategies thatdirect how an AM system will create a region of an object within eachlayer are not readily modifiable. For example, for a multipleirradiation device AM system, how two or more irradiation devices willcreate the region or interact to create the region is not easilymodifiable. Build strategy parameters can take a variety of forms. Oneexample build strategy parameter includes the location of a stitchingregion in an object in which two or more irradiation devices interact tobuild the object. Stitching regions can have an increased surfaceroughness or altered material properties that may not be desired to belocated in sensitive areas in certain objects, e.g., within a hole thatrequires precise dimensions or a smooth bearing surface. Conventionally,the location of stitching regions is automatically determined by one ofthe aforementioned AM file systems. Consequently, prevention of astitching region being located in a sensitive area within an objectcannot be easily controlled. Any changes require labor intensiverevision of the object code representative of the object. This challengeexists regardless of the category of additive manufacturing employed.

BRIEF DESCRIPTION OF THE INVENTION

A first aspect of the disclosure provides a computerized method formodifying object code representative of an object to be physicallygenerated layer by layer by a computerized additive manufacturing (AM)system using the object code, the computerized method comprising:providing an interface to allow a user to manually: select a regionwithin the object in the object code, the object code including aplurality of pre-assigned build strategy parameters for the object thatcontrol operation of the computerized AM system; and selectively modifya build strategy parameter in the selected region in the object code tochange an operation of the computerized AM system from the plurality ofpre-assigned build strategy parameters during building of the object bythe computerized AM system.

A second aspect of the disclosure provides a system for modifying objectcode representative of an object to be physically generated layer bylayer by a computerized additive manufacturing (AM) system using theobject code, the system comprising: a computing device providing aninterface to allow a user to manually: select a region within the objectin the object code, the object code including a plurality ofpre-assigned build strategy parameters for the object that controloperation of the computerized AM system; and selectively modify a buildstrategy parameter in the selected region in the object code to changean operation of the computerized AM system from the plurality ofpre-assigned build strategy parameters during building of the object bythe computerized AM system.

A third aspect of the disclosure provides a computerized additivemanufacturing (AM) system for physically generating an object layer bylayer based on object code representative of the object, the object codeincluding a plurality of pre-assigned build strategy parameters for theobject that control operation of the computerized AM system, thecomputerized AM system comprising: an additive manufacturing printer;and an object code modifier providing an interface to, prior tomanufacturing the object, allow a user to manually: select a regionwithin the object in the object code; and selectively modify a buildstrategy parameter in the selected region in the object code to changean operation of the computerized AM system from the plurality ofpre-assigned build strategy parameters during building of the object bythe computerized AM system.

A fourth aspect of the disclosure includes a computer program comprisingprogram code embodied in at least one computer-readable medium, whichwhen executed, enables a computer system to implement a computerizedmethod for modifying object code representative of an object to bephysically generated layer by layer by a computerized additivemanufacturing (AM) system using the object code, the computerized methodcomprising: providing an interface to allow a user to manually: select aregion within the object in the object code, the object code including aplurality of pre-assigned build strategy parameters for the object thatcontrol operation of the computerized AM system; and selectively modifya build strategy parameter in the selected region in the object code tochange an operation of the computerized AM system from the plurality ofpre-assigned build strategy parameters during building of the object bythe computerized AM system.

A fifth aspect of the disclosure provides a computerized method formodifying object code representative of an object to be physicallygenerated layer by layer by a computerized additive manufacturing (AM)system using the object code, the computerized method comprising:providing an interface to allow a user to manually: select a regionwithin the object in the object code, the object code including aplurality of pre-assigned build strategy parameters for the object thatcontrol operation of the computerized AM system; and selectively add abuild strategy parameter in the selected region in the object code tochange an operation of the computerized AM system from the plurality ofpre-assigned build strategy parameters during building of the object bythe computerized AM system.

The illustrative aspects of the present disclosure are designed to solvethe problems herein described and/or other problems not discussed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this disclosure will be more readilyunderstood from the following detailed description of the variousaspects of the disclosure taken in conjunction with the accompanyingdrawings that depict various embodiments of the disclosure, in which:

FIG. 1 shows a schematic block diagram of an illustrative additivemanufacturing environment according to embodiments of the disclosure.

FIG. 2 shows a schematic block diagram of an illustrative additivemanufacturing system and process including a non-transitory computerreadable storage medium storing object code representative of an objectaccording to embodiments of the disclosure.

FIG. 3 shows a schematic perspective view of a two irradiation deviceadditive manufacturing system building an object.

FIG. 4 shows a schematic plan view of respective fields of a fourirradiation device additive manufacturing system.

FIG. 5 shows a flow diagram of a computerized method according toembodiments of the disclosure.

FIG. 6 shows a schematic view of an illustrative interface for selectinga region according to embodiments of the disclosure.

FIG. 7 shows a schematic view of an illustrative interface including anexample selector for selecting a region according to embodiments of thedisclosure.

FIG. 8 shows a schematic view of an illustrative interface forselectively modifying a selected region according to embodiments of thedisclosure.

FIG. 9 shows a schematic view of an illustrative interface including anexample selector for selecting a region according to embodiments of thedisclosure.

FIG. 10 shows a schematic view of an illustrative interface forselectively modifying a selected region according to embodiments of thedisclosure.

FIG. 11 shows a schematic view of layers of an object includingselective modification(s) of a stitching region according to embodimentsof the disclosure.

FIG. 12 shows an enlarged schematic view of a layer of an objectincluding selective modification(s) of scan vector(s) and/or scan vectorend gap(s) according to embodiments of the disclosure.

FIG. 13 shows a schematic view of a selected region of a single layer(of many) of an object including selective modification(s) of scanvector(s) and/or scan vector end gap(s) according to other embodimentsof the disclosure.

FIG. 14 shows a schematic view of a layer of an object includingselective modification(s) of scan vector(s) and/or scan vector endgap(s) according to further embodiments of the disclosure.

FIG. 15 shows a schematic view of a layer of an object including otherselective modification(s) of scan vector(s) and/or scan vector endgap(s) according to further embodiments of the disclosure.

FIG. 16 shows a schematic view of an illustrative interface forselectively adding a build strategy parameter according to embodimentsof the disclosure.

It is noted that the drawings of the disclosure are not to scale. Thedrawings are intended to depict only typical aspects of the disclosure,and therefore should not be considered as limiting the scope of thedisclosure. In the drawings, like numbering represents like elementsbetween the drawings.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, the disclosure provides various methods, systems andprogram products that allow for selectively modifying a build strategyparameter in a selected region in object code for an object. The objectcode is used by a computerized additive manufacturing (AM) system tobuild the object. The selective modification of the build strategyparameter changes an operation of the computerized AM system from aplurality of pre-assigned build strategy parameters during building ofthe object. In this fashion, individual build strategy parameters can bereadily customized to address features of the object that arechallenging to build. This process is manual, not automated, whichallows a user to selectively modify build strategy parameters ratherthan relying on automated, pre-assigned build strategies. As will bedescribed, the selectively modified build strategy parameter can includepractically any aspect of how the computerized AM system will be used tobuild an object.

At the outset, several descriptive terms may be used regularly herein,and it should prove helpful to define these terms at the onset of thissection. These terms and their definitions, unless stated otherwise, areas follows. As used herein, “build strategy” refers to a plan for acomputerized AM system and how one or more printing devices thereof willbe used to build an object. Each build strategy may include a number ofbuild strategy parameters that direct how device(s) of a given additivemanufacturing (AM) system will be controlled. Each “build strategyparameter” controls one or more aspect(s) of how a particular printingdevice operates. For purposes of description, the disclosure will bedescribed relative to a direct metal laser melting (DMLM) AM techniqueusing a multiple irradiation device computerized AM system. In thisexample, and as will be described in greater detail with regard to FIGS.2-4, build strategy parameters may include but are not limited to:processing chamber temperature, pressure, etc.; irradiation beam width,speed, power; scan vector spacing, length and start/stop positions;irradiation device assignments; scan vector end gap spacing andpositioning; and stitching region position, size and shape/path. As willbe further described, the selected region upon which changes in a buildstrategy parameter can be applied can be user defined and can include,for example, an areal region (e.g., within each of at least one layer ofthe object or for particular scan vector(s), used to build the object)or a volume of the object (e.g., a number of layers). As used herein,“pre-assigned build strategy parameters” are those parameters generatedas part of the conversion of a CAD or other format representation of theobject into a format capable of use by an AM system to print the object;they may be automatically generated. To “modify” a build strategyparameter may include changing a pre-assigned build strategy parameteror adding a build strategy parameter.

FIG. 1 shows a schematic block diagram of an additive manufacturing (AM)environment 40 including an illustrative computerized additivemanufacturing system 100 (hereinafter ‘AM system 100’) according toembodiments of the disclosure. As will be described herein, a regionmodifier 90 that implements the teachings of the disclosure can belocated in a number of locations within AM environment 40. As noted,additive manufacturing techniques typically include taking athree-dimensional (3D) computer aided design (CAD) object file of theobject to be formed and preparing it for use by AM system 100. CADobject file 52 can be created in any now known or later developedfashion by using, e.g., a CAD system 50 to create it, a 3D scanner (notshown) that creates a raw object file 54, or digital photography andphotogrammetry software that creates raw object file 54. Raw object file54, for example, may undergo any necessary repair to address errors(e.g., holes, etc.) therein to arrive at CAD object file 52. In anyevent, CAD object file 52 that provides the 3D representation of theobject may be created (shown, for example, in CAD system 52) and mayhave any CAD format such as a Standard Tessellation Language (STL) file.

CAD object file 52 may require further preparation for use by an AMprinter 122 of AM system 100. To this end, preparation software 56 forcarrying out any necessary preparation of CAD object file 52 isillustrated. Preparation software 56 may be located at various locationsin AM environment 40. Preparation software 56 can carry out anyfunctions necessary to prepare CAD object file 52 into object code 124Othat can be used by AM printer 122 of AM system 100. (AM system 100generally includes an additive manufacturing control system 120(“control system”) and an AM printer 122). For example, preparationsoftware 56 may include a “slicer” that interprets CAD object file 52and electronically slices it to create a file (object code 124O) with atwo-dimensional image of each layer (including vectors, images orcoordinates) that can be used to manufacture the object. Object code124O, as will be described, may also include a variety of additionalcomputer executable instructions, and may undergo additional revisionsusing, for example, region modifier 90 according to embodiments of thedisclosure. Preparation software 56 may output object code 124O in anyformat capable of being used by the desired AM system 100. For example,the object code may be an STL file or an AMF file.

In some cases, CAD system 50 includes preparation software 56 capable ofpreparing CAD object file 52 into a format that can be used by AMprinter 122 of AM system 100. In one alternative, preparation software56 may be provided by a separate additive manufacturing (AM) preparationsystem 60, located between CAD system 50 and AM printer 100. In anotheralternative, preparation software 56 is integrated into code 124 ofcontrol system 120 of AM system 100—either as part of preparationsoftware 56 or as part of control system 120 functioning. In any event,a build strategy for the object is created that includes a plurality ofpre-assigned build strategy parameters 92 for use by AM printer 122 tobuild the object.

As illustrated in FIG. 1, a region modifier 90 capable of carrying outthe teachings of the disclosure can be located at any location at whichpreparation software 56 may be located. In addition, when regionmodifier 90 is provided as part of AM system 100, it may be implementedas part of control system 120 or at a machine code level within AMprinter 122. Further, region modifier 90 may be provided as a separateentity that interacts with AM system 100 (lower right of FIG. 1).

For purposes of description, the teachings of the disclosures will bedescribed relative to building object(s) 102 using a powder bed infusiontechnique in the form of DMLM, shown in FIGS. 2-4. Consequently, buildstrategy parameters that will be described for selective modificationaccording to embodiments of the disclosure will be those associated withDMLM, some of which were noted previously. While the description willreference DMLM and its related build strategy parameters, it isunderstood that the general teachings of the disclosure are equallyapplicable to many other additive manufacturing techniques including butnot limited to: other forms of metal powder additive manufacturing suchas direct metal laser sintering (DMLS), selective laser sintering (SLS)or electron beam melting (EBM); binder jetting; polymer printing and vatphotopolymerization. Each AM technique will likely have its ownparticular set of build strategy parameters.

FIG. 2 shows a schematic block diagram of an illustrative computerizedAM system 100 for generating an object(s) 102 using DMLM. (Regionmodifier 90 shown as separate entity only for brevity). Object(s) 102may include one large object or multiple objects, e.g., two objects102A, 102B as shown, of which only a single layer is shown. The exampleshown uses multiple irradiation devices, e.g., four 100 Watt ytterbiumlasers 110, 112, 114, 116, but it is emphasized and will be readilyrecognized that the teachings of the disclosure are equally applicableto an AM system 100 using any number of irradiation devices, i.e., oneor more. The teachings of the disclosures are also applicable to anyirradiation device, e.g., an electron beam, laser, etc., and many othertechniques of additive manufacture, e.g., binder dispenser, objectmaterial dispenser, curing laser, etc. Object(s) 102 are illustrated ascircular elements; however, it is understood that the additivemanufacturing process can be readily adapted to manufacture any shapedobject, a large variety of objects and a large number of objects on abuild platform 118. Any number of object(s) 102 can be built, e.g., oneor more.

As noted relative to FIG. 1, AM system 100 generally includes controlsystem 120 and an AM printer 122. As will be described, control system120 executes object code 124O to generate object(s) 102 using AM printer122. A region modifier 90 according to embodiments of the disclosure isshown as an independent system interacting with control system 120, butit could be located in any location described relative to FIG. 1, e.g.,as part of code 124. As a separate system, region modifier 90 can beconfigured to be AM system agnostic. Control system 120 is shownimplemented on computing device 126 as computer program code. To thisextent, computing device 126 is shown including a memory 130 and/orstorage system 132, a processor unit (PU) 134, an input/output (110)stitching region 136, and a bus 138. Further, computing device 126 isshown in communication with an external 110 device/resource 140 andstorage system 132. In general, processor unit (PU) 134 executescomputer program code 124 that is stored in memory 130 and/or storagesystem 132. While executing computer program code 124, processor unit(PU) 134 can read and/or write data to/from memory 130, storage system132, I/O device 140 and/or AM printer 122. Bus 138 provides acommunication link between each of the objects in computing device 126,and I/O device 140 can comprise any device that enables a user tointeract with computing device 126 (e.g., keyboard, pointing device,display, etc.). Computing device 126 is only representative of variouspossible combinations of hardware and software. For example, processorunit (PU) 134 may comprise a single processing unit, or be distributedacross one or more processing units in one or more locations, e.g., on aclient and server. Similarly, memory 130 and/or storage system 132 mayreside at one or more physical locations. Memory 130 and/or storagesystem 132 can comprise any combination of various types ofnon-transitory computer readable storage medium including magneticmedia, optical media, random access memory (RAM), read only memory(ROM), etc. Computing device 126 can comprise any type of computingdevice such as an industrial controller, a network server, a desktopcomputer, a laptop, a handheld device, etc.

It is recognized that each system in AM environment 40 in FIG. 1 (e.g.,CAD system 50, AM preparation system 60, AM system 100, and separateregion modifier 90) may include their own computer environment similarto that just described for AM system 100, and may communicate with othersystems of AM environment 40 using any now known or later developedcommunication pathways. Any computing device used can comprise anygeneral purpose computing article of manufacture capable of executingcomputer program code installed by a user (e.g., a personal computer,server, handheld device, etc.). In other embodiments, a computing devicecan comprise any specific purpose computing article of manufacturecomprising hardware and/or computer program code for performing specificfunctions, any computing article of manufacture that comprises acombination of specific purpose and general purpose hardware/software,or the like. In each case, the program code and hardware can be createdusing standard programming and engineering techniques, respectively. Thecomputing device(s) employed may take a variety of forms. For example,in one embodiment, the computing device may comprise two or morecomputing devices (e.g., a server cluster) that communicate over anytype of wired and/or wireless communications link, such as a network, ashared memory, or the like, to perform the various process steps of thedisclosure. When the communications link comprises a network, thenetwork can comprise any combination of one or more types of networks(e.g., the Internet, a wide area network, a local area network, avirtual private network, etc.). Network adapters may also be coupled tothe system to enable the data processing system to become coupled toother data processing systems or remote printers or storage devicesthrough intervening private or public networks. Modems, cable modem andEthernet cards are just a few of the currently available types ofnetwork adapters. Regardless, communications between the computingdevices may utilize any combination of various types of transmissiontechniques.

Continuing with FIG. 2, as noted, AM system 100 and, in particularcontrol system 120, executes program code 124 to generate object(s) 102.Program code 124 can include, inter alia, a set of computer-executableinstructions (herein referred to as ‘system code 124S’) for operating AMprinter 122 or other system parts, and a set of computer-executableinstructions (herein referred to as ‘object code 124O’) definingobject(s) 102 to be physically generated by AM printer 122. As describedherein, additive manufacturing processes begin with a non-transitorycomputer readable storage medium (e.g., memory 130, storage system 132,etc.) storing program code 124. System code 124S for operating AMprinter 122 may include any now known or later developed software codecapable of operating AM printer 122.

Object code 124O defining object(s) 102 may include a precisely defined3D model of an object. Object code 124O also includes a build strategyincluding plurality of pre-assigned build strategy parameters 92 (FIG.1), as will be described in greater detail herein. Object code 124O canbe generated from any of a large variety of well-known CAD systems 50(FIG. 1) (such as AutoCAD®, TurboCAD®, DesignCAD 3D Max, etc.), or anyAM preparation system 60 (FIG. 1). Further, certain AM systems 100 nowprovide control systems 120 capable of creating object code 124O, e.g.,from a CAD object file 52 (FIG. 1) or a raw object file 54 (FIG. 1). Inany event, object code 124O can include any now known or later developedfile format. Furthermore, object code 124O representative of object(s)102 may be translated between different formats. For example, objectcode 124O may include STL files or AMF files. Object code 124Orepresentative of object(s) 102 may also be converted into a set of datasignals and transmitted, received as a set of data signals and convertedto code, stored, etc., as necessary. Object code 124O may also be aninput to AM system 100 and may come from a part designer, anintellectual property (IP) provider, a design company, the operator orowner of AM system 100, or from other devices. In any event, controlsystem 120 executes system code 124S and object code 124O, dividingobject(s) 102 into a series of thin slices that assemble using AMprinter 122 in successive layers of material. Region modifier 90 maymodify object code 124O per embodiments of the disclosure prior tomanufacture by AM printer 122.

AM printer 122 may include a processing chamber 142 that is sealed toprovide a controlled atmosphere for object(s) 102 printing, e.g., a setpressure and temperature for lasers, a vacuum for electron beam melting,or another atmosphere for other forms of additive manufacture. A buildplatform 118, upon which object(s) 102 is/are built, is positionedwithin processing chamber 142. For the metal powder AM process exampleused herein, a number of irradiation devices 110, 112, 114, 116 areconfigured to melt layers of metal powder on build platform 118 togenerate object(s) 102. While four irradiation devices 110, 112, 114,116 will be described herein, it is emphasized that the teachings of thedisclosure are applicable to a system employing any number of devices,e.g., 1, 2, 3, or 5 or more.

Build strategy parameters for DMLM may include but are not limited to:irradiation beam width, speed, power; scan vector spacing, length andstart/stop positions; and where more than one irradiation device isemployed: irradiation device assignments, scan vector end gap (meltpool) spacing and positioning, and stitching region position, size andshape/path. To further explain, FIG. 3 and FIG. 4 show two examples ofscan vectors and fields for a multiple irradiation device AM system.FIG. 3 shows a schematic perspective view of irradiation devices of AMsystem 100 using two irradiation devices 110, 112, e.g., lasers. Duringoperation, the irradiation device(s) (dashed lines) are guided, e.g., byscanner mirrors for lasers or electromagnetic field/electric coils forelectron beams, along scan vectors (paths), which are indicated byarrows on a top surface of illustrative object 102. Internal scanvectors 202 melt inner regions 204 of object 120 that scan linearlyacross a layer, and a very thin border 206 is melted with one to threecontour scan vectors 208 that only follow a desired outer edge of thelayer. Build strategy parameters for the two irradiation device AMsystem used here can include, for example, irradiation beam width,speed, power, and scan vector 202, 208 spacing, length and start/stoppositions. (Beam width controls a width of the irradiation beamside-to-side.) These build strategy parameters are also applicable tosingle irradiation device AM systems. In FIG. 3, each laser 110, 112 hasits own field (1 and 2, respectively) upon which it can work. Eachirradiation device 110, 112 may work within only a small portion of itsrespective field at any given time. Each field and the scan vectors areassigned to one or the other device 110, 112 with an interface 210(within oval) where fields 1, 2 of pair of devices 110, 112 meet. Thus,build strategy parameters can further include, for example, irradiationdevice assignments. Where each scan vector 202 goes, a melt pool iscreated, and where each scan vector 202 stops, its melt pool stops.Thus, where two scan vectors, e.g., 202A, 202B, stop adjacent oneanother, a scan vector end gap 229 exists in which it is expected themelt pools will merge to create a solid object from the metal powder.Scan vector 202, 208 (hereinafter collectively referred to as “scanvector(s) 202”) spacing and positioning can also constitute buildstrategy parameters. Further, as noted, an irradiation device assignmentindicating which scan vector is made by which irradiation device is abuild strategy parameter. Each irradiation device 110, 112 is calibratedin any now known or later developed manner. Each irradiation device 110,112 has had its laser or electron beam's anticipated position relativeto build platform 118 correlated with its actual position in order toprovide an individual position correction (not shown) to ensure itsindividual accuracy. Interface 210 in body 222 of object 120 defines afirst portion 224 and a second portion 226 of body 222 made by differentirradiation devices 110, 112 of multiple irradiation device AM system100 during a single build. Here, fields 1, 2 meet at a line, creating aplanar interface 228 in object 102.

FIG. 4 shows a schematic plan view of irradiation devices of an AMsystem using four irradiation devices 110, 112, 114, 116, e.g., lasers,in which stitching regions are created. Here, each irradiation device110, 112, 114, 116 has a field 1, 2, 3 or 4 including a non-overlappingfield region 230, 232, 234, 236, respectively, in which it canexclusively melt metal powder, and at least one overlapping field regionor stitching region 240, 242, 244, 246 in which two or more devices canmelt metal powder. (Herein, boxed numbers of devices 110, 112, 114, 116indicate which device creates the shape illustrated thereabout). In thisregard, each irradiation device 110, 112, 114, 116 may generate anirradiation device beam (two shown, 160, 162, in FIG. 2), respectively,that fuses particles for each slice, as defined by object code 124O. Forexample, in FIG. 2, irradiation device 110 is shown creating a layer ofobject 102B using irradiation device 160 in one region, whileirradiation device 112 is shown creating a layer of object 102B usingirradiation device 162 in another region. In addition to those buildstrategy parameters described relative to FIG. 3, stitching regionposition, size and shape/path may also constitute build strategyparameters. Again, each irradiation device 110, 112, 114, 116 iscalibrated in any now known or later developed manner. That is, eachirradiation device 110, 112, 114, 116 has had its laser or electronbeam's anticipated position relative to build platform 118 correlatedwith its actual position in order to provide an individual positioncorrection (not shown) to ensure its individual accuracy. In oneembodiment, each of plurality irradiation devices 110, 112, 114, 116 maycreate an irradiation device beam, e.g., 160, 162 (FIG. 2), having thesame cross-sectional dimensions (e.g., shape and size in operation),power and scan speed; however, such build strategy parameters can beselectively modified according to embodiments of the disclosure. It isrecognized that while four devices 110, 112, 114, 116 have beenillustrated to describe a stitching region for overlapping fields, anytwo devices may create overlapping fields.

Returning to FIG. 2, an applicator 164 may create a thin layer of rawmaterial 166 spread out as the blank canvas from which each successiveslice of the final object will be created. Applicator 164 may move undercontrol of a linear transport system 168. Linear transport system 168may include any now known or later developed arrangement for movingapplicator 164. In one embodiment, linear transport system 168 mayinclude a pair of opposing rails 170, 172 extending on opposing sides ofbuild platform 118, and a linear actuator 174 such as an electric motorcoupled to applicator 164 for moving it along rails 170, 172. Linearactuator 174 is controlled by control system 120 to move applicator 164.Other forms of linear transport systems may also be employed. Applicator164 can take a variety of forms. In one embodiment, applicator 164 mayinclude a body 176 configured to move along opposing rails 170, 172, andan actuator element (not shown in FIG. 2) in the form of a tip, blade orbrush configured to spread metal powder evenly over build platform 118,i.e., build platform 118 or a previously formed layer of object(s) 102,to create a layer of raw material. The actuator element may be coupledto body 176 using a holder (not shown) in any number of ways. Theprocess may use different raw materials in the form of metal powder. Rawmaterials may be provided to applicator 164 in a number of ways. In oneembodiment, shown in FIG. 2, a stock of raw material may be held in araw material device 178 in the form of a chamber accessible byapplicator 164. In other arrangements, raw material may be deliveredthrough applicator 164, e.g., through body 176 in front of itsapplicator element and over build platform 118. In any event, anoverflow chamber 179 may be provided on a far side of applicator 164 tocapture any overflow of raw material not layered on build platform 118.In FIG. 2, only one applicator 164 is shown. In some embodiments,applicator 164 may be among a plurality of applicators in whichapplicator 164 is an active applicator and other replacement applicators(not shown) are stored for use with linear transport system 168. Usedapplicators (not shown) may also be stored after they are no longerusable.

In one embodiment, object(s) 102 may be made of a metal which mayinclude a pure metal or an alloy. In one example, the metal may includepractically any non-reactive metal powder, i.e., non-explosive ornon-conductive powder, such as but not limited to: a cobalt chromiummolybdenum (CoCrMo) alloy, stainless steel, an austenite nickel-chromiumbased alloy such as a nickel-chromium-molybdenum-niobium alloy(NiCrMoNb) (e.g., Inconel 625 or Inconel 718), anickel-chromium-iron-molybdenum alloy (NiCrFeMo) (e.g., Hastelloy® Xavailable from Haynes International, Inc.), or anickel-chromium-cobalt-molybdenum alloy (NiCrCoMo) (e.g., Haynes 282available from Haynes International, Inc.), etc. In another example, themetal may include practically any metal such as but not limited to: toolsteel (e.g., H13), titanium alloy (e.g., Ti₆Al₄V), stainless steel(e.g., 316L) cobalt-chrome alloy (e.g., CoCrMo), and aluminum alloy(e.g., AlSi₁₀Mg). In another example, the metal may include practicallyany reactive metal such as but not limited to those known under theirbrand names: IN738LC, Rene 108, FSX 414, X-40, X-45, MAR-M509, MAR-M302or Merl 72/Polymet 972.

The atmosphere within processing chamber 142 is controlled for theparticular type of irradiation device being used. For example, forlasers, processing chamber 142 may be filled with an inert gas such asargon or nitrogen and controlled to minimize or eliminate oxygen. Here,control system 120 is configured to control a flow of an inert gasmixture 180 within processing chamber 142 from a source of inert gas182. In this case, control system 120 may control a pump 184, and/or aflow valve system 186 for inert gas to control the content of gasmixture 180. Flow valve system 186 may include one or more computercontrollable valves, flow sensors, temperature sensors, pressuresensors, etc., capable of precisely controlling flow of the particulargas. Pump 184 may be provided with or without valve system 186. Wherepump 184 is omitted, inert gas may simply enter a conduit or manifoldprior to introduction to processing chamber 142. Source of inert gas 182may take the form of any conventional source for the material containedtherein, e.g. a tank, reservoir or other source. Any sensors (not shown)required to measure gas mixture 180 may be provided. Gas mixture 180 maybe filtered using a filter 188 in a conventional manner. Alternatively,for electron beams, processing chamber 142 may be controlled to maintaina vacuum. Here, control system 120 may control a pump 184 to maintainthe vacuum, and flow valve system 186, source of inert gas 182 and/orfilter 188 may be omitted. Any sensors (not shown) necessary to maintainthe vacuum may be employed. Other appropriate atmospheres may beprovided for other AM techniques, e.g., 3D printing.

A vertical adjustment system 190 may be provided to vertically adjust aposition of various parts of AM printer 122 to accommodate the additionof each new layer, e.g., a build platform 118 may lower and/or chamber142 and/or applicator 164 may rise after each layer. An extent to whichvertical adjustment system 190 moves may also be a build strategyparameter. Vertical adjustment system 190 may include any now known orlater developed linear actuators to provide such adjustment that areunder the control of control system 120.

In operation, build platform 118 with metal powder thereon is providedwithin processing chamber 142, and control system 120 controls theatmosphere within processing chamber 142. Any aspect of atmosphericcontrol within processing chamber 142 may also constitute a buildstrategy parameter. Control system 120 also controls AM printer 122, andin particular, applicator 164 (e.g., linear actuator 174) andirradiation device(s) 110, 112, 114, 116 to sequentially melt layers ofmetal powder on build platform 118 to generate object(s) 102 accordingto object code 124O. As noted, various parts of AM printer 122 mayvertically move via vertical adjustment system 190 to accommodate theaddition of each new layer, e.g., a build platform 118 may lower and/orchamber 142 and/or applicator 164 may rise after each layer.

While FIGS. 2-4 have been described herein to provide an understandingof build strategy parameters, e.g., relative to the DMLM additivemanufacturing technique. It is emphasized that other additivemanufacturing techniques may employ different build strategy parameters.For example, in binder jetting, a binder liquid flow rate may constitutea build strategy parameter, or in 3D polymer printing, a temperature ofpolymer may constitute a build strategy parameter.

With reference to FIGS. 2-4, the flow diagram of FIG. 5, andnon-limiting examples shown in FIGS. 6-14, a computerized method formodifying object code 124O representative of object 102 to be physicallygenerated layer by layer by computerized AM system 100 using the objectcode, will now be described. At the outset, object code 124O includesplurality of pre-assigned build strategy parameters 92 for object 102that control operation of computerized AM system 100. That is, objectcode 124O has undergone some level of preparation for additivemanufacture in which a build strategy therefore has been created. Forexample, irradiation device assignments are made, irradiation devicebeam width, speed and power are assigned, and scan vector spacing, andstart/stops are known. Typically, this process occurs with AM system 100through use of some form of AM preparation system. This process may alsoinclude any now known or later developed computerized slicing techniqueof object 102 into layers for additive manufacture. That is, object code124O may include a layer by layer representation of object 102, eachlayer to be sequentially, physically generated by AM system 100.

In a first process S10 in FIG. 5, region modifier 90 provides aninterface 250 (FIGS. 6-7) to allow a user to manually select a region246 (FIG. 7) within object 102 in object code 124O. The providing ofinterface 250 by region modifier 90, as noted herein, may occur at anyof a number of locations such as but not limited to: at AM system 100(FIGS. 1-2); at CAD system 50 (FIG. 1); or at AM preparation system 60apart from AM system 100. Interface 250 (FIGS. 6-7) may be provided inany manner I/O device 140 (FIG. 2) can accommodate. Further, region 246may be selected using any now known or later developed manner ofinputting a two-dimensional or three-dimensional geographic selectioninto a computing device, e.g., via I/O device 140 for computing device126 (FIG. 2). FIGS. 6 and 7 show one embodiment of a two-dimensionalselection of region 246, and FIG. 9 shows one embodiment of athree-dimensional selection of region 266.

In FIGS. 6 and 7, a portion of object 102, e.g., a layer 248 (slice) ora portion thereof, can be illustrated in an interface 250. Here, regionmodifier 90 may provide interface 250 in the form of a graphical userinterface (GUI) 252 showing layer 248 of object 102 to a user to allowthe user to select region 246 as a two-dimensional area of layer 248 inwhich build strategy parameters will be selectively modified. As shownin FIG. 6, where possible, GUI 252 may illustrate pre-assigned buildstrategy parameters 92 in any now known or later developed fashion,e.g., color, textual indicators, dimensional indicators, mapping marks,tables, dropdown menus, etc. For example, in FIG. 6, irradiation device110 assignment for all of layer 248 is noted textually (boxed number),and a scan vector spacing (i.e., space between adjacent scan vectors)may be indicated with color, e.g., blue, or cross-hatching. Although notshown, GUI 252 may include a large variety of textual indications ofpractically any desired additional pre-assigned build strategyparameters 92, e.g., via an interactive table or listing. In the GUIembodiment, region 246 can be selected using any now known or laterdeveloped manner in which a portion of an image can be selected in GUI252. In the example shown in FIG. 7, a square cropping box 256 isemployed; however, any other size or shape selector may be employed.Further, a freehand cropping tool may be employed for more precision. Inanother embodiment, one or more ranges of coordinates may be numericallyinput to select region 246. While region 246 has been shown as a squaretwo-dimensional area in FIG. 7, region 246 can take on practically anyform including but not limited to: a line, a dot or particular scanvector(s) 202. While a singular region 246 has been described asselected, it is emphasized that process S10 can be repeated as manytimes as modifications are desired, e.g., for a number of layers ofobject 102, for a number of regions within a layer, for a number of scanvectors within a layer, etc. Where more than one region 246 is selectedin more than one layer, collectively, the selected region may extendvertically within object 102, e.g., where the same region of a number ofadjacent layers is selected.

In process S12 in FIG. 5, region modifier 90 provides interface 260(FIG. 8) to allow a user to manually selectively modify a pre-assignedbuild strategy parameter in selected region 246 in object code 124O tochange an operation of computerized AM system 100 from plurality ofpre-assigned build strategy parameters 92 during building of the objectby the computerized AM system. Interface 260 may be the same as thatprovided to select region 246, or may be a different interface entirely,e.g., a textual input, a table input. The modification can be of anybuild strategy parameter applicable to region 246. In one example shown,plurality of pre-assigned build strategy parameters 92 may include atleast one pre-assigned irradiation device assignment for each layer ofobject 102 (e.g., 110 for layer 248 in FIG. 6), and the selectivemodification may include changing the at least one pre-assignedirradiation device assignment within region 246. In the example shown inFIG. 8, some of internal scan vectors 202 of region 246 (FIG. 7) may bere-assigned to be built by irradiation device 112 (boxed number), ratherthan irradiation device 110. The modification can be made in any nowknown or later developed fashion of changing parameters in a GUI, e.g.,by input into an entry of a table of pre-assigned build strategyparameters 92, by selecting a different indicator from a dropdown menu,by drag and drop techniques, etc.

Referring to FIGS. 9 and 10, an embodiment for selecting athree-dimensional region 261 of object 102 is illustrated. Here, regionmodifier 90 may provide GUI 250 (FIG. 9) showing a volume 262 (total orportion) of object 102 to a user to allow the user to select region 266as a three-dimensional area of volume 262 in which pre-assigned buildstrategy parameters 92 will be selectively modified. As shown in FIG. 9,where possible, GUI 250 may illustrate pre-assigned build strategyparameters 92 in any now known or later developed fashion, e.g., color,textual indicators, dimensional indicators, mapping marks, tables,dropdown menus, etc. For example, in FIG. 9, irradiation device 110assignment for the left half of volume 262 and irradiation device 112assignment for the right half of volume 262 are noted textually (boxednumbers), and a stitching region 264 is illustrated with a dashed cubeor lines. GUI 252 may include a large variety of textual indications ofpractically any desired additional pre-assigned build strategyparameters 92, e.g., via an interactive table or listing. In the GUIembodiment, region 261 can be selected using any now known or laterdeveloped manner in which a three-dimensional portion of an image can beselected in GUI 252. In the example shown in FIG. 9, an elongatedcropping cube 268 is employed; however, any other size or shape croppingselector may be employed. Further, a freehand cropping tool may beemployed for more precision. In another embodiment, one or more rangesof coordinates may be numerically input to define region 261. Whileregion 261 has been shown as an elongated cubical three-dimensionalvolume in FIG. 9, region 261 can take on practically anythree-dimensional form including preset three-dimensional forms, e.g., asphere, or a particular portion of object 102, e.g., a shroud of anairfoil.

In process S12 in FIG. 5, region modifier 90 provides interface 270(FIG. 10) to allow a user to manually selectively modify a buildstrategy parameter in selected region 261 (FIG. 9) in object code 124Oto change an operation of computerized AM system 100 from plurality ofpre-assigned build strategy parameters 92 during building of the objectby the computerized AM system. The providing of interface 270 by regionmodifier 90, as noted herein, may occur at any of a number of locationssuch as but not limited to: at AM system 100 (FIGS. 1-2); at CAD system50 (FIG. 1); or at AM preparation system 60 apart from AM system 100.Interface 270 may be the same as that provided to select region 261, ormay be a different interface entirely, e.g., a textual input, a tableinput. In the example shown in FIG. 10, a size and/or shape of stitchingregion 264 is modified to avoid opening(s) 272 in object 102. Themodification can be made in any now known or later developed fashion ofchanging parameters in a GUI, e.g., by input into an entry of a table ofpre-assigned build strategy parameters 92, by selecting a differentindicator from a dropdown menu, by drag and drop techniques, byselecting and modifying visually renderable build strategy parameters(e.g., stitching region position), etc.

While singular regions 246, 261 have been described as selected, it isemphasized that process S10 can be repeated as many times asmodifications are desired, e.g., for a number of regions of object 102.For example, selected region 246 (FIG. 7) may include a plurality ofregions, and the layer to which it is addressed may include a pluralityof layers, and each region may include a selectively modified buildstrategy parameter.

In process S14 in FIG. 5, object code 124O is used to build object 102with the selectively modified build strategy parameter usingcomputerized AM system 100. The build may proceed in any now known orlater developed fashion appropriate for the type of additivemanufacturing employed, but using the build strategy parameter(s) asselectively modified according to embodiments of the disclosure.

Referring to FIGS. 11-14, embodiments of some illustrative pre-assignedbuild strategy parameters 92 for multiple irradiation device AM systemsand related build strategy modifications will now be described. As notedherein, AM system 100 may include at least two irradiation devices 110,112, 114, 116 (FIG. 2). Where two irradiation devices are employed, theselected region (246 in FIG. 7 or 261 in FIG. 9) may include a stitchingregion 264 (FIG. 9) to be created by the at least two irradiationdevices, e.g., 110, 112 in FIG. 9. Here, build strategy parameter(s)control operation of the irradiation devices of the computerized AMsystem relative to the stitching region.

Referring to FIG. 11, a portion of a first layer 284 of object 102 isshown superimposed next to a portion of a second, adjacent layer 286 ofobject 102 to illustrate an example selective modification relative to astitching region 282. Here, a selected region 280 encompassing stitchingregion 282 may extend vertically across a plurality of layers of theobject (e.g., like region 261 in FIG. 9). Selected region 280 includesstitching region 282 in which two irradiation devices 110, 112 each maycreate object 102. First layer 284 may represent, for example, oddnumbered layers, and second layer 286 may represent even numbered layers(or vice versa) of object 102.

With reference to FIG. 11 along with FIGS. 9 and 10, various embodimentsof the disclosure include selectively modifying a position of stitchingregion 282 in selected region 280 of one or more layers 284, 286 ofobject 102 from plurality of pre-assigned build strategy parameters 92(FIG. 2). For example, conventional pre-assigned build strategyparameters 92 (FIG. 2) typically indicate a stitching region should bebuilt vertically upon itself in each layer of object 102, like stitchingregion 264 in FIG. 9. The assignment of the position of a stitchingregion per conventional pre-assigned build strategy parameters 92 (FIG.2) does not consider avoiding object 102 features in which stitchingregion existence is not ideal, e.g., openings 272 in FIG. 9. In oneembodiment, shown in FIG. 11, the selective modification according toone embodiment of the disclosure may include assigning a first position288 for stitching region 282 in first layer 284 of object 102, andassigning a second, different position 290 for stitching region 282 in asecond, different layer 286 of object 102. In this manner, stitchingregion position switches in each layer and issues arising from stitchingregion 282 being built upon itself in the same area in each layer can beavoided. For example, while not necessary in all instances, in FIG. 11,first position 288 of stitching region 282 in first layer 284 does notoverlap with second, different position 290 of stitching region 282 insecond, different layer 286. Here, first position 288 may be on a firstlateral side of a centerline C of selected region 280, and second,different position 290 may be on a second, different lateral side ofcenterline C of selected region 280. In this manner, stitching region282 position shifts from first position 288 to second, differentposition 290 as object 102 is built, creating a less rough surface at anouter surface of object 102 and perhaps creating a stronger object 102due to the geographic distribution of stitching region 282.

In another embodiment, the build strategy parameter selective modifyingmay include modifying a size of stitching region 264 in selected region261 of layer(s) of object 102 from the plurality of pre-assigned buildstrategy parameters 92 (FIG. 2). This selective modification can beobserved by comparing stitching region 264 in FIG. 9, having a width W1,to stitching region 264 in FIG. 10 after modification having a differentwidth W2 (smaller in example shown). FIG. 10 also shows anotherembodiment including modifying a shape (or path) of stitching region 264in selected region 261 of layer(s) of object 102 from the plurality ofpre-assigned build strategy parameters 92 (FIG. 2). In FIG. 10,stitching region 264 curves around openings 272 in object 102, comparedto extending linearly through openings 272 in FIG. 9. FIG. 10 also showsanother, simpler embodiment of modifying a position of stitching region264 in selected region 266 of layer(s) of object 102 from plurality ofpre-assigned build strategy parameters 92 (FIG. 2) compared to FIG. 11.That is, in FIG. 10, stitching region 264 is moved laterally in somespots to avoid openings 272 in object 102, compared to extending throughopenings 272 in FIG. 9. The modifications shown can be made, forexample, by drag and drop techniques, or textual inputs.

Referring to FIGS. 12 and 13, in another embodiment, build strategyparameter modifying may include modifying a characteristic of one ormore scan vector end gaps 302 among a plurality of spaced scan vectorend gaps 300 created by at least two irradiation devices, e.g., 110, 112(FIG. 2). More particularly, FIGS. 12 and 13 show scan vectors 202A,202B each formed by at least two irradiation devices, e.g., scan vectors202A formed by one irradiation device (e.g., 110 in FIG. 2), and scanvectors 202B formed by another irradiation device (e.g., 112 in FIG. 2).As shown best in FIG. 12, scan vectors 202A, 202B define a scan vectorend gap 300 in a spaced between melt pool ends 310, 314 of the scanvectors. That is, each scan vector end gap 300 is defined between afirst melt pool end 310 of a first irradiation device (e.g., 110 forscan vectors 202A) in stitching region 312 (FIG. 13) and a second,abutting melt pool end 314 of a second, different irradiation device(e.g., 112 for scan vectors 202B) in stitching region 312 (FIG. 13).Each scan vector end gap 300 may have a width W_(G). As noted,conventional pre-assigned build strategy parameters 92 (FIG. 2)typically indicate a stitching region should be built vertically uponitself in each layer of object 102, like stitching region 264 in FIG. 9.In this case, scan vector end gaps 300 typically are aligned verticallywithin a stitching region, creating a planar area in object 102 in whichthe gaps are stacked upon one another. In accordance with anotherembodiment of the disclosure, scan vector end gaps 300 may beselectively modified by changing their size, e.g., by increasing ordecreasing any one or more of them in width. That is, the build strategyparameter modifying may include modifying a size (W_(G)) of at least oneof the plurality of spaced, scan vector end gaps 300. In this fashion,where it is advantageous, for example, to have scan vector end gapscloser together or farther apart, e.g., to strengthen an area or toavoid some object feature, the change can be selectively made. As willbe understood, changing positions of scan vector end gaps also changesthe length of certain scan vectors 202. The modification can be made,for example, by drag and drop techniques, or textual inputs.

In another embodiment shown in FIG. 13, stitching region 312 may have acenterline C defining a first half 320 and a second half 322 thereof inselected region 324. Here, build strategy parameter modifying mayinclude alternatingly positioning the plurality of spaced, scan vectorend gaps 300 in first half 320 and second half 322 of stitching region324. That is, each scan vector end gap 300 is in a different half ofstitching region 324 than adjacent scan vector end gaps. In thisfashion, scan vector end gaps 300 do not overlap within stitching region312. In another embodiment, shown in FIG. 14, the build strategyparameter modifying may include randomly selecting a position of theplurality of spaced scan vector end gaps 300 between first half 320 andsecond half 322 of stitching region 312. That is, positions of scanvector end gaps 300 are arbitrarily selected. The selected region withinwhich scan vector modifications are made can be an areal region, avolume or even select scan vector(s).

As noted, embodiments of the disclosure may be applicable to AM systemsemploying any number of irradiation devices 110, 112, 114, 116,including one. In this regard, certain build strategy parameters areused for both single and multiple irradiation device AM systems. Thefollowing description addresses some examples of those build strategyparameters.

With continuing reference to FIG. 14, in another embodiment, theplurality of pre-assigned build strategy parameters 92 (FIG. 2) mayinclude a set of preset scan vector parameters for each layer of object102. Each set of preset scan vector parameters may include, for example,scan vector spacing, scan vector width, scan vector length, scan vectorpath, e.g., linear or curved, interior or boundary, etc. In this case,step S10 may include selecting a region including one or more scanvectors 202. That is, the selected region is defined by at least onescan vector used to build object 102 in object code 124O. For example,selected region 324 may be an areal space including a number of scanvectors 202A, 202B, 202X as in FIG. 14, or a single scan vector such asscan vector 202X. In step S12, the selective modifying may includechanging at least one scan vector parameter from the set of preset scanvector parameters for the region of the layer of the object. Forexample, the build strategy parameter modifying may include changing abeam size of at least one irradiation device 110, 112, 114, 116 for theregion, e.g., one or more scan vectors 202 in the region, from theplurality of pre-assigned build strategy parameters. Alternatively, abeam size of a single scan vector 202X may be changed (shown wider).FIG. 15 shows another example in which spacing between certain scanvectors 202 (which are selected regions) have been selectively modified,e.g., they are not equally spaced.

Referring to FIG. 16, an illustrative interface 250 in the form of a GUI252, created by region modifier 90, is shown. In this example, a twodimensional representation of selected region 246 of a layer of anobject 102 with, for example, laser assignments, e.g., 110, 112, andstitching region 264, is shown. A dropdown window 350 may provide a listof pre-assigned build strategy parameters 92, e.g., laser assignment(assign), spacing, width, etc., allowing selection of one or morepre-assigned build strategy parameters for modification. An input window352 may be provided for modifying a selected pre-assigned build strategyparameter 92. In addition, a build strategy parameter add window 356 maybe created by region modifier 90 with a list of build strategyparameters 358 that can be added. The list of build strategy parametersto be added 358 may include those not listed in the pre-assigned buildstrategy parameters 92. An appropriate input window 360 may also becreated by region modifier 90 for inputting an appropriate value for theselected additional build strategy parameter(s) 358. A selector 362 maybe provided for GUI-based selecting, dragging, reshaping actions, etc.,relative to positions of visually rendered and modifiable build strategyparameters such as the position of stitching region 264. It is notedthat the example GUI 252 is just one example of a large variety of wellunderstood techniques for modifying and/or adding build strategyparameters.

As will be appreciated by one skilled in the art, embodiments of thepresent disclosure (e.g., region modifier 90) may be embodied as asystem, method or computer program product. Accordingly, the presentdisclosure may take the form of an entirely hardware embodiment, anentirely software embodiment (including firmware, resident software,micro-code, etc.) or an embodiment combining software and hardwareaspects that may all generally be referred to herein as a “circuit,”“module” or “system.” Furthermore, the present disclosure may take theform of a computer program product embodied in any tangible medium ofexpression having computer-usable program code embodied in the medium.

Any combination of one or more computer usable or computer readablemedium(s) may be utilized. The computer-usable or computer-readablemedium may be, for example but not limited to, an electronic, magnetic,optical, electromagnetic, infrared, or semiconductor system, apparatus,device, or propagation medium. More specific examples (a non-exhaustivelist) of the computer-readable medium would include the following: anelectrical connection having one or more wires, a portable computerdiskette, a hard disk, a random access memory (RAM), a read-only memory(ROM), an erasable programmable read-only memory (EPROM or Flashmemory), an optical fiber, a portable compact disc read-only memory(CD-ROM), an optical storage device, a transmission media such as thosesupporting the Internet or an intranet, or a magnetic storage device.Note that the computer-usable or computer-readable medium could even bepaper or another suitable medium upon which the program is printed, asthe program can be electronically captured, via, for instance, opticalscanning of the paper or other medium, then compiled, interpreted, orotherwise processed in a suitable manner, if necessary, and then storedin a computer memory. In the context of this document, a computer-usableor computer-readable medium may be any medium that can contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The computer-usable medium may include a propagated data signal with thecomputer-usable program code embodied therewith, either in baseband oras part of a carrier wave. The computer usable program code may betransmitted using any appropriate medium, including but not limited towireless, wireline, optical fiber cable, RF, etc.

Computer program code for carrying out operations of the presentdisclosure may be written in any combination of one or more programminglanguages, including an object oriented programming language such asJava, Smalltalk, C++ or the like and conventional procedural programminglanguages, such as the “C” programming language or similar programminglanguages. The program code may execute entirely on the user's computer,partly on the user's computer, as a stand-alone software package, partlyon the user's computer and partly on a remote computer or entirely onthe remote computer or server. In the latter scenario, the remotecomputer may be connected to the user's computer through any type ofnetwork, including a local area network (LAN) or a wide area network(WAN), or the connection may be made to an external computer (forexample, through the Internet using an Internet Service Provider).

The present disclosure is described herein with reference to flowdiagram illustrations and/or block diagrams of methods, systems andcomputer program products according to embodiments of the disclosure. Itwill be understood that each block of the flow diagram illustrationsand/or block diagrams, and combinations of blocks in the flow diagramillustrations and/or block diagrams, can be implemented by computerprogram instructions. These computer program instructions may beprovided to a processor of a general purpose computer, special purposecomputer (e.g., control system 120 of AM system 100, or region modifier90), or other programmable data processing apparatus to produce amachine, such that the instructions, which execute via the processor ofthe computer or other programmable data processing apparatus, createmeans for implementing the functions/acts specified in the flow diagramand/or block diagram block or blocks. In this regard, each block in theflow diagram or block diagrams may represent a module, segment, orportion of code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flow diagram illustration,and combinations of blocks in the block diagrams and/or flow diagramillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

These computer program instructions may also be stored in acomputer-readable medium that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instruction meanswhich implement the function/act specified in the flow diagram and/orblock diagram block or blocks. The computer program instructions mayalso be loaded onto a computer or other programmable data processingapparatus to cause a series of operational steps to be performed on thecomputer or other programmable apparatus to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flow diagram and/orblock diagram block or blocks.

The technical advantage of embodiments of the disclosure is to provide atechnique to manually selectively modify a selected region of an objectin object code used for additive manufacture. This functionality is incontrast to automated systems that change object code for a specificpurpose without user intervention. In one embodiment, the presentdisclosure allows for multiple irradiation devices to work on a singleobject or portion of an object where the user can specifically definebuild strategy parameters for the stitching region between theirradiation devices. The user has manual control of, for example, thestitching region locations, stitching characteristics, and balance ofwork between the multiple irradiation devices. Embodiments of thedisclosure also allow for a customization of selected regions defined ona scan vector by scan vector basis. Embodiments of the disclosure areCAD model driven and allow direct scan path editing techniques. Thedisclosure is applicable to a wide variety of additive manufacturingtechniques.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or objects, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, objects,and/or groups thereof. “Optional” or “optionally” means that thesubsequently described event or circumstance may or may not occur, andthat the description includes instances where the event occurs andinstances where it does not.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about,” “approximately” and “substantially,” are notto be limited to the precise value specified. In at least someinstances, the approximating language may correspond to the precision ofan instrument for measuring the value. Here and throughout thespecification and claims, range limitations may be combined and/orinterchanged, such ranges are identified and include all the sub-rangescontained therein unless context or language indicates otherwise.“Approximately” as applied to a particular value of a range applies toboth values, and unless otherwise dependent on the precision of theinstrument measuring the value, may indicate +/−10% of the statedvalue(s).

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A system for modifying object code representativeof an object to be physically generated layer by layer by a computerizedadditive manufacturing (AM) system having a first and a secondirradiation device using the object code, the system comprising: acomputing device providing an interface to allow a user to manually:select a stitching region within the object in the object code, theobject code including a plurality of pre-assigned build strategyparameters for the object that control operation of the computerized AMsystem; and selectively modify a build strategy parameter in theselected stitching region in the object code to change an operation ofthe computerized AM system from the plurality of pre-assigned buildstrategy parameters during building of the object by the computerized AMsystem, wherein the modifying includes modifying a scan vector end gapamong a plurality of spaced scan vector end gaps defined between: afirst melt pool end of a first scan vector formed by the firstirradiation device in the stitching region, and a second abutting meltpool end of a different scan vector formed by the second irradiationdevice, wherein the plurality of spaced scan vector end gaps arealternatingly positioned in the stitching region.
 2. The system of claim1, further comprising the computerized AM system for using the objectcode to build the object with the selectively modified build strategyparameter.
 3. The system of claim 1, wherein the stitching regionextends vertically across a plurality of layers of the object, and theselective modifying includes assigning a first position for thestitching region in a first layer of the object, and assigning a second,different position for the stitching region in a second, different layerof the object.
 4. The system of claim 3, wherein the first position ofthe stitching region in the first layer does not overlap with thesecond, different position of the stitching region in the second,different layer.
 5. The system of claim 3, wherein the first position ison a first lateral side of a centerline of the stitching region, and thesecond, different position is on a second, different lateral side of thecenterline of the stitching region.
 6. The system of claim 1, whereinthe build strategy parameter selective modifying includes modifying aposition of the stitching region in the layer of the object from theplurality of pre-assigned build strategy parameters.
 7. The system ofclaim 1, wherein the build strategy parameter selective modifyingincludes modifying a size of the stitching region in the layer of theobject from the plurality of pre-assigned build strategy parameters. 8.The system of claim 1, wherein the build strategy parameter selectivemodifying includes modifying a shape of the stitching region in thelayer of the object from the plurality of pre-assigned build strategyparameters.
 9. The system of claim 1, wherein the stitching region has acenterline defining a first half and a second half of the stitchingregion in the region, and wherein the build strategy parameter modifyingincludes alternatingly positioning the plurality of spaced, scan vectorend gaps in the first half and the second half of the stitching region.10. The system of claim 1, wherein the build strategy parametermodifying includes modifying a size of at least one of the plurality ofspaced, scan vector end gaps.
 11. The system of claim 1, wherein theplurality of pre-assigned build strategy parameters includes at leastone pre-assigned irradiation device assignment for each layer of theobject, and wherein the selectively modifying includes changing the atleast one pre-assigned irradiation device assignment within the region.12. The system of claim 1, wherein the plurality of pre-assigned buildstrategy parameters includes a set of preset scan vector parameters foreach layer of the object, and wherein the build strategy parameterselective modifying includes changing at least one scan vector parameterfrom the set of preset scan vector parameters for the stitching regionof the layer of the object.
 13. The system of claim 1, wherein the buildstrategy parameter modifying includes changing a beam size of the firstand second irradiation device for the stitching region from theplurality of pre-assigned build strategy parameters.
 14. The system ofclaim 1, wherein the selected stitching region is defined by at leastone scan vector used to build the object in the object code.
 15. Thesystem of claim 1, wherein the selected stitching region is defined byone of an areal space within each of at least one layer of the object inthe object code, or a volume of the object within the object code. 16.The system of claim 1, wherein the object further comprises the layerhaving a plurality of layers and the stitching region having a pluralityof stitching regions, each of the plurality of stitching regionsincluding a selectively modified build strategy parameter.
 17. Thesystem of claim 1, wherein the object code includes a layer by layerrepresentation of the object, each layer to be sequentially, physicallygenerated by the computerized AM system.
 18. The system of claim 1,wherein the computing device includes the computerized AM system, andthe providing occurs at the computerized AM system after the object codeis input to the computerized AM system.
 19. The system claim 1, whereinthe computing device includes a computer aided design (CAD) system, andthe providing occurs as part of functioning of the CAD system.
 20. Thesystem of claim 1, wherein the computing device includes an additivemanufacturing preparation system, and the providing occurs as part offunctioning of the additive manufacturing preparation system.